In the technology of integrated circuits, interest is directed to higher packing densities and/or faster switching speeds. In addition to a continuing development of traditional CMOS technique in this direction, other components are being increasingly proposed with which this goal can possibly be more expediently achieved. What are referred to as single electron components are thereby considered to be especially promising, these working with what is referred to as a Coulomb blockade. For example, an overview of such single electron components may be derived from the article by A. Gladun et al., Physik in Unserer Zeit 23 (1992), p. 159.
Such single electron components comprise one or more nodes that can only be charge-reversed via high-impedance potential barriers. This charge reversal can be effected by the quantum-mechanical tunnel effect or by a thermally activated transfer.
The charge reversal of a node having a total capacitance C by an elementary charge e corresponds to a charge transport of one electron over the potential barrier. In order to recharge the node by one elementary charge e, an energy expenditure on the order of magnitude of e.sup.2 /C is required. When the thermal energy k.sub.B T (k.sub.B is the Boltzmann constant and T is the absolute temperature) of the system is far, far lower than this energy expenditure, i.e. k.sub.B T&lt;&lt;e.sup.2 /C, then this charge transfer is prohibited. A charge transfer is only possible by applying an adequately high, external voltage.
An estimate for the overall capacitance of the system derives from k.sub.B T&lt;&lt;e.sup.2 C. C &lt;&lt;4.multidot.10.sup.-16 F=0.4 aF derives at the temperature of liquid helium, T=4.2 K. Single electron components that can be operated at room temperature must have an even lower capacitance. C&lt;&lt;6.multidot.10.sup.-18 F=6 aF derives for room temperature T=300.degree. K.
Various components that utilize this effect have been proposed: a single electron transistor, a turn stile device, an electron pump, a single electron memory.
Whether or not these components can achieve significance on an industrial scale is dependent on whether the problem of manufacturing such low capacitances with suitable potential barriers can be satisfactorily solved.
It has been proposed (see, for example, P. Lafarge et al., Z. Phys. B 85 (1991) p. 327) to employ aluminum striplines having optimally small dimensions for manufacturing single electron components. They were structured with electron beam lithography. Tunnel barriers of Al.sub.x O.sub.y are employed as potential barriers, these being arranged between two overlapping striplines. Such tunnel barriers exhibit capacitances of around 10.sup.-15 F=1 fF, so that these components must be operated at temperatures of around T=20 mK.
Another proposal is comprised in generating a 2-dimensional electron gas (2 DEG) in gallium arsenide, either by a delta doping or a heterostructure. Electron beam lithography is again utilized for lateral structuring. Capacitances of 2.multidot.10.sup.17 F . . . 2.multidot.10.sup.-16 F.vertline.=20 . . . 200 aF can be achieved in this way. It has therefore been proposed to locally deplete the 2-dimensional electron gas by employing a gate and to thus realize the potential barrier. The height of the potential barrier can thereby be set with external voltages.
H. Matsuoka et al., IEDM 92, p. 781, has disclosed a component in silicon MOS technique in which single electron effects have been observed. The component comprises a MOS transistor having a first gate electrode whose length between source and drain amounts to approximately 5 .mu.m and whose width perpendicular thereto amounts to 0.13 .mu.m. This MOS transistor therefore exhibits an extremely small width. A second gate electrode is arranged in a second level, this second gate electrode comprising ridges proceeding transversely over the first gate electrode that each respectively comprise a width of 0.14 .mu.m and a mutual spacing of 0.16 .mu.m. The transistor channel can be constricted by lateral field influence by applying a corresponding control voltage to the second gate electrode. Measured characteristics are thereby interpreted such that a series of nodes arise upon constriction that are respectively separated from one another via potential barriers and such that a Coulomb blockade occurs: The first and the second gate electrode in this arrangement are structured by electron beam lithography. An adjustment of the second electron beam lithography to the first electron beam lithography must thereby occur, this involving increased processing expense.